<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    var str1 = "Hello"
    var str2 = "World"
    var str3 = "Kobe"

    console.log(str1.concat(" ", str2, " ", str3))
    console.log(str1.concat(str2).concat(str3))

    console.log("    coderwhy    ".trim()) // 删除首尾空格

    console.log("Hello World".split(" ")) //  ['Hello', 'World']

    console.log("Hello World".split(" ").join("-")) // Hello-World

  </script>
</body>

</html>